In a few weeks, the fall crop of yard signs for school levies will begin to sprout in front yards. Their appearance will kick up the eternal debates: whether schools have too little or too much money. We'll argue over the disparities and whose fault it is if some students don't seem to learn much in the classroom. We'll split into camps about how to fix things, insisting money has nothing to do with it or everything to do with it.

As incessantly as Ohioans have debated the K-12 school financing system in the past decade, few of us grasp the basics, let alone the nuances, of the problem. As Achieve, Inc., observed in a report earlier this year, we just don't know enough about how money and resources are used within the school system for anyone to say with confidence that Ohio is getting the best results for the money it puts into the system.

A study panel of the State Board of Education likewise noted ''the opacity'' of the funding system, which makes it difficult to sustain a useful conversation on the issue.

To the extent that studies can follow the labyrinth and shed light on how financial decisions in local districts influence the quality of instruction and achievement, everyone gains, students, taxpayers and lawmakers all.

Which brings me to a study released this month by the Buckeye Institute for Public Policy Solutions, a conservative think tank based in Columbus.

The institute's examination of spending in 72 Ohio school districts in the 2005-06 school year helps to illuminate one of the more contentious issues in education: the disparities in academic achievement and the systemic roots of the problem in the unequal distribution of resources among school buildings within local districts.

It is safe to say the question of academic disparity (between high- and low-poverty districts and between white and minority students) has shown a capacity to get people really exercised because it seems to touch all the nerves in the educational body: race and culture, privilege and (dis)advantage and institutional policies and practices that affect the allocation of resources to districts and among buildings within districts.

The Buckeye study (''Shortchanging Disadvantaged Students: An analysis of intra-district spending patterns in Ohio'') took up the equity questions that have dogged the Statehouse. Despite increased spending on supplemental programs such as Poverty Based Assistance, academic performance in high-poverty and high-minority districts remains well below those in low-poverty and low-minority schools.

The study concluded that in the 72 districts studied, decisions at the district level diverted nearly $300 million in state money that should have been spent in individual schools on disadvantaged, gifted and special needs students. Funds earmarked for such students were not reaching their targets, the students with the greatest needs, in nearly three-quarters of districts.

The study identified collective bargaining agreements as a major contributor to the inequities, the results of the agreements having broad impact on school budgets and teacher assignments. Seniority-based transfer policies, for instance, concentrate the most experienced and best paid teachers in wealthier and low-minority buildings.

The Buckeye study is not the first to trace the patterns of distribution that severely shortchange poor and minority districts. The Achieve report talked about Ohio's ''district-centric'' funding approach which, it said, is ''typically inequitable,'' producing inequalities that may be ''significantly shortchanging disadvantaged students'' and denying poor schools access to the most highly qualified teachers.

The annual Funding Gap reports by Education Trust, a national policy research group, has tracked disparities in resource allocation arising from various policies, including teacher salaries and the degree of dependence on locally generated funds (say, property and income taxes).

The Buckeye study's summary conclusion comes down to this: If inequity persists in the state school funding system, it is not the fault of the state but the result of decisions and patterns of funding perpetuated by local officials and unions.

The study has added local data, confirming for skeptics the systemic roots of disparities in school performance. Unfortunately, the study also virtually absolved the state from any further responsibility, leaving the impression that in the funding allocations it has made to date, Ohio has done all it should and needs to do.